refactor: make shared_qobject_ptr ctor explicit

This turns issues like creating two shared ptrs from a single raw ptr
from popping up at runtime, instead making them a compile error.

Signed-off-by: flow <flowlnlnln@gmail.com>

launcher/ui/pages/modplatform/ResourceModel.cpp

@@ -265,7 +265,7 @@ std::optional<QIcon> ResourceModel::getIcon(QModelIndex& index, const QUrl& url)
         return { pixmap };
 
     if (!m_current_icon_job)
-        m_current_icon_job = new NetJob("IconJob", APPLICATION->network());
+        m_current_icon_job.reset(new NetJob("IconJob", APPLICATION->network()));
 
     if (m_currently_running_icon_actions.contains(url))
         return {};